Abstract: Frequently changing pseudonym is commonly accepted as a solution to protect privacy in Vehicular Ad hoc NETworks（VANETs）. To against the low effectiveness of most changing pseudonym algorithms, an effective algorithm of changing pseudonyms simultaneously is proposed. In the algorithm, a bit “wait flag” is inserted into the information that vehicles periodically broadcast, which is used to improve the probability of changing pseudonyms simultaneously, thereby to improve the successful rate of changing pseudonyms. Simulation results show that the algorithm can effectively improve the successful rate of changing pseudonyms, thus it enhances the effectiveness of changing pseudonyms to strengthen privacy protection of vehicles.

Key words: Vehicular Ad hoc NETworks（VANET）, changing pseudonyms, privacy protection

摘要： 在车载自组织网络中，频繁更改伪码是一种被广泛接受的保护隐私方法。针对目前大部分更改伪码算法的有效性较低的问题，提出了一种有效的同时更改伪码算法。该算法通过在车辆周期性广播的信息中插入一个等待标识比特来提高车辆同时更改伪码的概率，从而提高更改伪码的成功率。模拟结果表明，该算法能够显著提高更改伪码的成功率，从而提高更改伪码的有效性，增强车辆的隐私保护。

关键词: 车载自组织网络, 更改伪码, 隐私保护